The present invention relates generally to electroactive polymers that convert between electrical energy and mechanical energy. More particularly, the present invention relates to pre-strained electroactive polymers.
In many applications, it is desirable to convert between electrical energy and mechanical energy. Exemplary applications requiring conversion from electrical to mechanical energy include robotics, motors, pumps, valves, speakers, sensors, microfluidic devices, general automation, disk drives, and prosthetic devices. These applications include one or more transducers that convert electrical energy into mechanical work—on a macroscopic or microscopic level. Exemplary applications requiring conversion from mechanical to electrical energy include sensors and generators.
New electroactive polymers capable of converting electrical energy to mechanical energy, and vice versa, are available for a wide range of energy conversion applications. Electroactive elastomers, one specific class of electroactive polymer, may exhibit high energy density, stress, and electromechanical conversion efficiency. The performance of many electroactive polymers is notably increased when the polymer is pre-strained.
Pre-strain traditionally required deformation of the polymer by stretching the polymer in tension and fixing one or more polymer edges while stretched. Sturdy and bulky support structures such as frames were commonly used to hold the pre-strain. Mechanisms, such as a spring, have also been used in a rolled electroactive polymer device to support polymer pre-strain. The dependence on frames and external mechanisms decreases power density of electroactive polymers and their related devices.
In view of the foregoing, alternative techniques to acquire and maintain pre-strain in an electroactive polymer would be desirable.